Action Points

Note that this study was published as an abstract and presented at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.

The use of long-lasting pesticide-treated nets as framed screening in houses in mosquito-infested areas of Mexico significantly reduced the presence of the insects and their larvae in homes.

Note that the screening of the homes in Merida on the Yucatan Peninsula appeared to reduce indoor adult Aedes aegypti mosquitoes -- known carriers of dengue and chikungunya pathogens -- in households by about 59% compared with control homes without the netting.

PHILADELPHIA -- The use of long-lasting pesticide-treated nets as framed screening in houses in mosquito-infested areas of Mexico significantly reduced the presence of the insects and their larvae in homes, researchers reported here.

Mendez also told MedPage Today that for an average cost per home of about $20 the screening project achieved a 38% extended reduction of A. aegypti in home over the first year (P<0.05), and reduced adult-indoor mosquito populations by 71% compared to controls over the next 12 to 24 months.

The homes that were screened also showed a significant decline in levels of immature A. aegypti with a 70% reduction observed in mosquito larvae and/or pupae (P<0.05) and a 71% reduction in pupae per person (P<0.05).

"The protections of houses with long-lasting insecticidal screens permanently installed lead to reductions in A. aegypti infestation levels, particularly reducing vector infestation and abundance at the household level in Merida for at least 2 years after their implementation," Mendez said.

The nets were installed in 750 households; another 1,000 homes were used as controls, Mendez and colleagues reported. The screens were made from Duranet Clarke material and were 100% polyethylene nonflammable mesh, with an insecticide content of 0.55% alpha-cypermethrin. The screens were permanently installed on external doors and windows. The average dwelling had 1.9 doors protected and 4.9 windows protected with the screen netting.

The research team conducted five cross-sectional entomological surveys in the interventional and control houses starting in September 2012, and then again at 8 months, 13 months, 19 months, and 25 months. The surveys were timed to occur in alternating wet and dry seasons.

The researchers are continuing to monitor the individuals in the homes to determine if the netting that reduces populations of potentially pathogen-carrying mosquitoes also reduces incidence of the diseases.

"This is a fantastic study that shows you can use simple measures to reduce risk of disease in these communities," said Kacey Ernst, PhD, MPH, of the University of Arizona, Tucson. "There are always a number of questions with these measures, including the sustainability of the projects and while $20 doesn't seem like much it can stretch the budget of people with low incomes."

Ernst told MedPage Today she would also be interested in seeing the follow-up on how much the screens reduce the illness burden, and to see how long the screening continues to work to protect the households from mosquito infestation. She also said the installation of the screens would have to be simplified and standardized in order to get widespread coverage.

"We also need to know how well the families accepted the appearance of the screens on their windows and doors, whether the installation was aesthetically pleasing," she said.

Donna Armellino, RN, DNP, vice president for infection prevention at North Shore-LIJ Health System, Great Neck, NY, told MedPage Today, "Most of us would believe that intuitively if you put screens on a window you will keep mosquitoes from coming into the home environment. It is interesting that this really was a controlled study, and they proved the hypothesis of the study. As long as the screens are put on the windows it will reduce infestation. It is always good to have evidence to support what you thought would occur."

Armellino said that if you decrease the mosquitoes in the home "you will decrease the risk of disease." She said that with the relatively small numbers of homes involved, it may be difficult to show there is a corresponding decrease in illness -- at least until such a project is adopted on a community-wide basis.

Mendez, Armellino, and Ernst disclosed no relevant relationships with industry.

Reviewed by Robert Jasmer, MD Associate Clinical Professor of Medicine, University of California, San Francisco and Dorothy Caputo, MA, BSN, RN, Nurse Planner

Accessibility Statement

At MedPage Today, we are committed to ensuring that individuals with disabilities can access all of the content offered by MedPage Today through our website and other properties. If you are having trouble accessing www.medpagetoday.com, MedPageToday's mobile apps, please email legal@ziffdavis.com for assistance. Please put "ADA Inquiry" in the subject line of your email.